How Bradford pear threatens open lands

“Callery pear seedlings are moving further and further into the countryside, away from the suburbs and cities from whence the problem sprang,” writes Brett O’Brien, Natural Resources Supervisor for Columbia, Missouri Department of Parks & Recreation.

Here is why MoIP is choosing to focus attention on Bradford pear this year:

1. Callery pear goes feral, fast.

In our previous blog post, we discussed how Callery pear trees establish easily, being very well adapted to a variety of soil types and environmental conditions. We also mentioned how different Callery cultivars can cross-pollinate and produce fertile seeds, which birds carry into new areas.

It’s not just a matter of two full-grown cultivars crossing genes.

South Carolina landscape designer Durant Ashmore explains it best:

However, the dangerous nature of Bradford pears is not the worst problem this tree possesses. As it turns out, Bradford pears are not sterile. They crossbreed indiscriminately with every other kind of pear in the environment. They are grafted on to common pear root stock. This root stock will sucker and flower itself, and this crossbreeds with Bradford pear.

Also, in a misguided effort to lessen the dangers of Bradford pear, other pears with branch structures slightly more resistance to splitting apart were introduced to the market. Pear trees such as Aristocrat, Chanticleer and Cleveland Select were introduced. Once these trees were introduced, the disaster exploded exponentially.

2. Feral pear is a thorny mess.

When thinking about invasive plants from an ecological perspective, the most important aspect is how they displace native plants communities.

Again, Durant Ashmore:

Because of the cross pollination problem, pear trees have now proliferated exponentially across our environment. And, to make matters worse, the evil offspring has reverted to the ancient Chinese Callery pears which form impenetrable thorny thickets that choke out the life out of pines, dogwoods, maples, redbuds, oaks, hickories, etc.

When you see those fields of white flowering trees, please don’t get giddy with excitement over pretty white flowers. What you are looking at are Callery pears destroying nature. Callery pears have 4 inch thorns. They can’t be mowed down. Those thorns will shred John Deere tractor tires. They can only be removed by steel tracked dozers, decreasing the value of agricultural or forest land to the tune of $3,000 per acre.

3. Without control, invasive ornamental pear trees take over quickly

If different cultivars of Callery pears are grown in proximity, they can cross-pollinate and produce fertile seeds, carried by birds into new areas.

This fact sheet from the Missouri Department of Conservation says it well:

Callery pear is adapted to a wide variety of environmental conditions, including heavy clay soils, drought, heat and pollution. Growing best in full sun, it also tolerates partial shading. Spreading into open, disturbed habitats, naturalization occurs within early successional fields, parks, rights of way, power lines and other natural open areas. It grows rapidly, flowers at a young age, often develops thorns and produces large amounts of seed. It is also establishing in the understory of forests and woodlands and is able to flower and fruit in small canopy openings.

The seed bank and sprouting ability of Bradford pear persists for years after cutting or treatment, so further management is needed beyond the first treatment.

4. There seems to be no stopping them.

Current laws do not address up-and-coming invasive plants such as Callery pear and Amur honeysuckle. Only 12 species are regulated under the Missouri Plant Law. Historically, the Noxious Weed List refers to agricultural pests. Listing a weed, especially a suburban species, is problematic because it would likely mean that a high percentage of homeowners are on the hook for removing or controlling that plant. To make changes to the Missouri Plant Law, such as creating a new designation of weeds that are banned from sale, would require changing statutes through the legislative process.

If you see something, say something!